It has long been known that alpha olefins can be produced from aluminum alkyls by displacement of the alkyls as alpha olefins by reaction of aluminum alkyl with a different olefin under suitable reaction conditions. One type of process involves thermal displacement wherein the displacing olefin and aluminum alkyl are reacted at 280.degree.-320.degree. C. to effect the displacement. Such processes require raped cooling to about 120.degree. C. to minimize isomerization and other undesired side reactions. A process of this type is described in Davis et al. U.S. Pat. No. 3,391,219.
The other type of displacement processes involves use of a catalyst to facilitate the displacement reaction. One such process is described in Diefenbach et al. U.S. Pat. No. 4,918,254. In that process the displacement is catalyzed by use of a nickel catalyst in a reaction wherein preferably at least a 200 percent excess (i.e., 9 moles of olefin per mole of AlR.sub.3) and more preferably at least a 500 percent excess of displacing olefin is used over the stoichiometric amount required to replace all alkyl groups of the aluminum alkyl. As the patentees indicate, such large excesses of displacing olefin are used because the displacement reaction is an equilibrium reaction. Thus use of large excesses is intended to shift the equilibrium so that the alkyl substitution in the second trialkyl aluminum will more closely approach the distribution of the displacing olefin.